CFA Level 3 2015 Q7 Part B Derivative Query and General Query!

Hello All,

I have a query regarding 2015 Q7 Part b I am confused regarding how to use sign.Why is FV negative and PV is positive ?I follow FV is positive and PV is negative notation.Also why are taking after tax return ?

Also from the same paper Q9 part B standard deviation why it is saying that standard deviation of USD and EUR will be same (15%).I am confused can anyone advise?